1. Field of the Invention
The present invention relates to a sheet supplying apparatus for separating and supplying sheets resting on a sheet stacking member, one by one, by using a supply rotary member, and more particularly, it relates to a sheet guide member capable of positively separating and supplying thin sheets or thick sheets one by one, a sheet supplying apparatus on which such a sheet guide can be mounted, and an image forming apparatus on which such a sheet guide member can be mounted.
2. Related Background Art
In many image forming apparatuses, such as copying machines, facsimiles and printers, which have now been used, a plurality of recording sheets are stacked on a sheet stacking member and the sheets are separated and supplied, one by one, to form an image on the sheet. In such apparatuses, in order to separate and supply the stacked sheets one by one, there have been proposed a so-called pawl separation mechanism in which a pawl is provided at an end of a sheet cassette and the sheets are separated, one by one, by contacting corners of the sheets supplied by a supply roller and a so-called retard separation mechanism, in which the sheets are separated, one by one, by a supply roller rotated in a sheet supplying direction and a retard roller rotated in a sheet returning direction, by utilizing friction between the sheets.
However, in the above-mentioned pawl separation mechanism, the position of the pawl must be changed in accordance with a sheet-width size. On the other hand, the above-mentioned retard separation mechanism makes the apparatus bulky and complicated.
To solve the above problems, another separation means has been proposed, as disclosed in the Japanese Patent Application Laid-Open No. 8-40590. In this separation means, a thin plate made of Myler and the like is used to cause sheets supplied by a supply roller to thereby urge thereagainst, so that the sheets are separated, one by one, by flexing or deflecting the thin plate. This separation means can separate relatively thick sheets and relatively thin sheets.
However, very thick sheets and very thin sheets cannot be separated effectively with such separation means.